Blow mold unit, blow molding machine and method for replacing blow mold unit

ABSTRACT

A blow mold unit including: a blow mold including first and second blow cavity split molds and a plurality of raised bottom molds; first and second pressure receiving members; first and second fixing plates to which the first and second blow cavity split molds and the first and second pressure receiving members are respectively fixed; a third fixing plate interposed between the first and second fixing plates and to which the raised bottom molds are fixed at a first surface thereof; a pressure receiving rod extending down from a second surface; and a placement portion fixed to at least one of the first and second fixing plates and placing the third fixing plate thereon when the first and second blow cavity split molds are closed. The pressure receiving rod includes a first engaging portion engageable with a second engaging portion in a vertical direction.

TECHNICAL FIELD

The present invention relates to a blow mold unit, a blow moldingmachine using the same and a method for replacing the blow mold unit.

BACKGROUND ART

In a blow molding machine, a mold must be replaced according containersto be blow molded. As a blow mold for blow molding a container from apreform, a pair of blow cavity split molds is necessary. In addition, inorder that the bottom portion of a blow molded container can have a socalled champagne bottom shape, a self-supporting bottle shape or asimilar shape projecting inwardly, a raised bottom mold is necessary asa blow mold. Also, in some cases, separately from the pair of blowcavity split molds, a raised bottom mold which is clamped by the pair ofblow cavity split molds is necessary.

Patent document 1 discloses a blow mold unit in which a pair of blowcavity and a raised bottom mold can be handled as an integral body whenreplacing molds.

CITATION LIST Patent Document

Patent Document 1: JP-A-2011-156728

DISCLOSURE OF THE INVENTION Problems that the Invention is to Solve

In an embodiment of the patent document 1, among one of first and secondmold clamping plates to which a blow mold unit is fixed, one clampingplate is fixed and only the other clamping plate is driven. Since theraised bottom mold is supported on the fixed mold clamping plate, evenwhen the first and second blow cavity split molds are opened during moldreplacement, the raised bottom mold is prevented from falling off.

However, in a case of a blow mold unit mounted onto first and secondmold clamping plates, which moves in line symmetry by a moldclamping/mold opening device of a blow molding machine, when the firstand second mold clamping plates are opened, there exists no member forsupporting the raised bottom mold from the lower side. Therefore,another member for preventing the raised bottom mold from falling offbecomes necessary.

It is an object of the invention to provide a blow mold unit, which isto be mounted onto first and second mold clamping plates movable in linesymmetry by the mold clamping/mold opening device of a blow moldingmachine, in which, even when first and second blow mold cavity splitmolds are opened during mold replacement, it is not necessary to addanother member in order to prevent a raised bottom mold from fallingoff, a blow molding machine using the same, and a method for replacingthe blow mold unit.

Means for Solving the Problems

(1) One aspect of the invention relates to a blow mold unit to beconnected to first and second mold clamping plates movable in linesymmetry by a mold clamping/mold opening device of a blow moldingmachine and an elevation device of the blow molding machine, the blowmold unit including:

a blow mold including first and second blow cavity split molds to beclamped by bringing parting surfaces thereof into contact with eachother, and a plurality of raised bottom molds that define a plurality ofraised bottom shapes for a plurality of cavities defined by the firstand second blow cavity split molds;

first and second pressure receiving plates that receive mold clampingpressure by bringing parting surfaces thereof into contact with eachother;

a first fixing plate to which the first blow cavity split mold and thefirst pressure receiving plate are fixed and to be connected to thefirst mold clamping position;

a second fixing plate to which the second blow cavity split mold and thesecond pressure receiving plate are fixed and to be connected to thesecond mold clamping position;

a third fixing plate interposed between the first and second fixingplates and to which the plurality of raised molds are fixed at a firstsurface thereof;

a pressure receiving rod hanging down from a second surface of the thirdfixing plate opposed to the first surface; and

a placement portion fixed to at least one of the first and second fixingplates and placing the third fixing plate thereon when the first andsecond blow cavity split molds are closed,

wherein the pressure receiving rod includes an engaged portionengageable with an engaging portion, which is formed to an elevation rodof the elevation device, in a vertical direction.

According to the one aspect of the invention, when the blow mold unit iscarried into and out from the blow molding machine, the first and secondblow cavity split molds are closed. At such time, the third fixing platefor fixing the plurality of raised bottom molds is placed on theplacement portion fixed to at least one of the first and second fixingplates. Thus, since not only the first and second blow cavity splitmolds and the first and second pressure receiving plates but also theplurality of raised bottom molds through the placement portion and thirdfixing plate are held the first and second fixing plates, they can behandled as an integral body during mold replacing. This blow mold unitis carried into the blow molding portion of the blow molding machine asan integral body. Further, when the first and second fixing plates arefixed to the first and second mold clamping plates of a moldclamping/mold opening device provided to the blow molding machine, andthe first and second fixing plates are then opened, the engaged portionof the pressure receiving rod fixed to the third fixing plate is engagedwith the engaging portion formed to the elevation rod of the elevationdevice provided to the blow molding machine in the vertical direction.Accordingly, the plurality of raised bottom molds, third fixing plateand pressure receiving rod are supported by the elevation rod. In thisstate, since the first and second blow cavity split molds are opened, anoperation space can be secured, whereby the engaged portion of thepressure receiving rod and the engaging portion of the elevation rod canbe connected to each other by the coupling member. In this way, theoperation to mount the blow mold unit onto the blow molding machine isended. The mold clamping drive of the plurality of raised bottom moldscan be realized by driving the elevation rod extending from the thirdfixing plate by the elevation rod of the elevation device of the blowmolding machine.

(2) In the one aspect of the invention, a tapered surface can be formedon at least one of the engaged portion of the pressure receiving rod andthe engaging portion of the elevation rod, and the engaging portion cancenter and guide the engaged portion.

Since the tapered surface is formed on at least one of the engagedportion and engaging portion, the engagement between the engaged portionand engaging portion in the vertical direction can performed smoothlyand the engaged portion can be centered at the position of the engagingportion.

(3) In the one aspect of the invention, the placement portion caninclude third and fourth pressure receiving plates that receive the moldclamping pressure by bringing the parting surfaces thereof into contactwith each other, the third pressure receiving plate can be fixed to thefirst fixing plate, and the fourth pressure receiving plate can be fixedto the second fixing plate. Accordingly, the placement portion can alsobe used as a pressure receiving plate.

(4) In the one aspect of the invention, the first and second pressurereceiving plates can each include: a roller rollingly contacting with abase of the blow molding machine; and a roller drive member that drivesthe roller to lower from an elevated position where the roller do notproject from a lower-most surface of the blow mold unit to a loweredposition where the roller rollingly contacts with the base.

Since this roller is set at the lowered position, by driving the rollerof the blow mold unit to roll on the base of the blow molding machine incontact therewith, the blow mold unit can be mounted and removed. Whenthe roller is lifted relatively after the blow mold unit is carried into a given position, the blow mold unit is lowered, whereby a part ofthe engaged portion can be engaged with the engaging portion. Afterthen, by driving the first and second fixing plates to open, while theengaged portion being guided by the engaging portion, the engaged statebetween the engaged portion and the engaging portion can be furtherpromoted.

(5) In the one aspect of the invention, the first pressure receivingplate can be fixed to the first fixing plate at both sides of the firstblow cavity split mold, the second pressure receiving plate can be fixedto the second fixing plate at both sides of the second blow cavity splitmold, slide metals can be respectively fixed to the lower-most surfacesof the first and second pressure receiving plates, the slide metal caninclude a pin insertable into a hole formed in one of the lower-mostsurfaces of the first and second pressure receiving plates and a screwhole to which a bolt is threadedly engaged in one of the first andsecond pressure receiving plates, and the first and second pressurereceiving plates can respectively include a hollow portion, a bolt holecan be formed to penetrate from an upper surface facing the hollowportion to the lower-most surface, and the bolt can be inserted into thebolt hole from the upper side and is threadedly engaged to the screwhole.

The slide metals are interposed between the lower-most surface of theblow mold unit and the base of the blow molding machine and are used toreduce the sliding friction of the blow mold unit on the base of theblow molding machine to thereby secure the smooth movement of the blowmold unit when the blow mold unit is closed, clamped and opened. Theneck mold provided in the blow molding machine and first and second blowcavity split molds are temporarily clamped to determine whether theheight of the first and second cavity split molds is proper or not. Whennot proper, the shim plates are inserted between the lower-most surfacesof the first and second pressure receiving plates and slide metals tothereby adjust the height of the blow mold unit. In this case, since thebolts for fixing the slide metals can be operated from the upper side ofthe base of the blow molding machine, the operating performance can beenhanced.

Further, when the blow mold unit including a roller is used, by settingthe roller at its lowered position when adjusting the height of the blowmold unit, a clearance capable of inserting the shim plates between thelower-most surfaces of the first and second pressure receiving platesand slide metals can be easily secured.

(6) Another aspect of the invention relates to a blow molding machineincluding:

a base;

the above-described blow mold unit according which is supported on thebase;

a mold clamping/mold opening device provided on the base and drives thefirst and second fixing plates of the blow mold unit to clamp/open thefirst and second blow cavity split molds; and

an elevation device that drives an elevation rod to lift and lower theplurality of raised bottom molds of the blow mold unit.

According to the other aspect of the invention, due to theabove-mentioned operation of the blow mold unit according to the oneaspect, a burden on the operation to replace the blow mold unit can bereduced greatly.

(7) A further other aspect of the invention relates to a method forreplacing a blow mold unit, the method including:

a step of carrying the above-described blow mold unit into between thefirst and second mold clamping plates movable in line symmetry by a moldclamping/mold opening device provided to a blow molding machine;

a step of fixing the first and second fixing plates of the blow moldunit to the first and second mold clamping plates of the moldclamping/mold opening device;

a step of driving the mold clamping/mold opening device to open thefirst and second blow cavity split molds; and

a step of coupling together the pressure receiving rod and the elevationrod including the engaging portion engaged with the engaged portion ofthe receiving rod by a coupling member.

According to the further other aspect of the invention, the blow moldunit can be carried into the blow molding machine as an integral body.Also, when the first and second blow cavity split molds are openedduring replacement of the blow mold unit, the engaged portion of thepressure receiving rod is engaged with the engaging portion formed inthe elevation rod of the elevation device provided in the blow moldingmachine from the vertical direction. Thus, since the plurality of raisedbottom molds, third fixing plate and pressure receiving rod aresupported by the elevation rod, the clamping operation by the couplingafter that can be executed easily.

(8) A further other aspect of the invention relates to a method forreplacing a blow mold unit, the method including:

a step of carrying the above-described blow mold unit into between thefirst and second mold clamping plates movable in line symmetry by a moldclamping/mold opening device provided to a blow molding machine, whilerolling the roller of the blow mold unit in contact with a base of theblow molding machine;

a step of fixing the first and second fixing plates of the blow moldunit to the first and second mold clamping plates of the moldclamping/mold opening device;

a step of driving the mold clamping/mold opening device to open thefirst and second blow cavity split molds; and

a step of coupling together the pressure receiving rod and the elevationrod including the engaging portion engaged with the engaged portion ofthe receiving rod by a coupling member.

According to the further other aspect of the invention, the blow moldunit can be carried into the blow molding machine as an integral bodyand also in such a manner that its friction during the carry-inoperation is reduced by the roller. After then, when the roller is setat its lifted position, the blow mold unit is lowered and a part of theengaged portion is engaged with the engaging portion. Next, when thefirst and second blow cavity split molds respectively connected to themold clamping/mold opening device are opened, the engaged portion of thepressure receiving rod fixed to the third fixing plate is engaged withthe engaging portion from the vertical direction while being guided bythe engaging portion. Thus, since the plurality of raised bottom molds,third fixing plate and pressure receiving rod are supported by theelevation rod, the clamping operation by the coupling after that can beexecuted easily.

(9) In the further other aspect of the invention, the method can furtherinclude a step of temporarily clamping a neck mold provided to the blowmolding machine and the first and second blow cavity split molds anddetermine whether a height of the first and second blow cavity splitmolds is proper or not, and when not proper, after the first and secondblow cavity split molds are opened, loosening the clamped state betweenthe first and second fixing plates and the first and second moldclamping plates, lowering the roller, and inserting shim plates intobetween the lower-most surfaces of the first and second pressurereceiving plates and the slide metals, thereby adjusting a height of theblow mold unit.

According to the further other aspect of the invention, since the rolleris set at the lowered position also when adjusting the height of theblow mold unit, a clearance capable of inserting the shim plates betweenthe lower-most surfaces of the first and second pressure receivingplates and slide metals can be easily secured.

Effects of the Invention

According to the invention, there can be provided a blow mold unit,which is to be mounted on first and second mold clamping plates movablein line symmetry by the mold clamping/mold opening device of a blowmolding machine, in which, even when first and second blow cavity splitmolds are opened during the mold replacing, it is not necessary to addanother member in order to prevent the raised bottom mold from fallingoff, a blow molding machine using the same, and a method for replacingthe blow mold unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a blow molding machine according to anembodiment of the invention.

FIG. 2 is a partially broken front view of the blow molding machineshown in FIG. 1.

FIG. 3 is a section view taken along the line shown in FIG. 1.

FIG. 4 is a front view of a blow mold unit.

FIG. 5 is a side view of the blow mold unit.

FIG. 6 is a plan view of the blow mold unit.

FIGS. 7A and 7B are a front view and a plan view of a slide metalrespectively.

FIG. 8 is a side view of the blow mold unit, showing the mounted stateof the slide metals.

FIG. 9A shows a state where the blow mold unit is carried-in, and FIG.9B is an explanatory view of a blow mold unit height adjusting step.

FIG. 10 is a section view showing the opened states of first and secondblow cavity split molds while the blow mold unit is being mounted.

FIG. 11 is a side view showing the blow mold unit height adjusting step.

FIG. 12 is a bottom view of the blow mold unit showing a blow mold unitheight adjusting step to be executed by using shim plates, from whichthe slide metals are omitted.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the invention will be specificallydescribed. Here, the embodiments described hereinafter do not limit thecontents of the invention disclosed in the scope of the appended claims.All of structures described in the embodiments are not always essentialas the solving means of the invention.

1. Blow Molding Machine

Firstly, description is given of an example of a blow molding machine towhich the invention is applied. FIG. 1 shows, for example, a blowmolding machine 50 of four stations. The molding machine 50, as shown inFIGS. 2 and 3, includes a machine base 52, a lower base 54, an upperbase 56, a traction plate 58, and a cylinder fixing plate 60, while theupper base 56, traction plate 58 and cylinder fixing plate 60 areconnected and fixed by a plurality of, for example, four tie bars 62(see FIG. 1) penetrating through the lower base 54.

The machine base 52 has a hollow box shape, while an injection apparatus64 is mounted on one side of the upper surface of the machine base 52.The lower base 54 is fixed to the upper surface of the other side of themachine base 52. The upper base 56 is disposed above the lower base 54with a given clearance between them and rotatably supports a rotaryplate 66 on the lower surface side thereof.

The upper base 56 is also connected and fixed to intermediate positionsof the two tie bars 62 on the injection apparatus 64 side and the upperends of the two tie bars 62 on the opposite side to the injectionapparatus 64.

A plurality of processing stations 1C˜4C are arranged at the pluralityof rotation stop positions of the rotary plate 66 existing in a spacebetween the lower and upper bases 54 and 56 above the machine base 52.As shown in FIG. 1, an injection molding station 68(1C) is formed on theinjection apparatus 64 side, a blow molding station 70(3C) is formed ata position opposite to the station 68(1C), and a temperature regulatingstation 72(2C) and a take-out station 74(4C) are formed at positionsintersecting at 90° with the injection molding station 68 and blowmolding station 70.

In the injection molding station 68, as shown in FIG. 2, an injectioncavity mold 78 is mounted on the lower base 54 through a hot runner mold76 nozzle-touchable with the injection apparatus 64.

In the blow molding station 70, similarly as shown in FIG. 2, there isprovided on the lower base 54 a blow mold 84 constituted of a split moldwhich can be mold clamped by a blow mold clamping mechanism (moldclamping/mold opening device) 82 including a blow mold clamping cylinder80. Here, a raised bottom mold is not shown in FIG. 2.

In the temperature regulating station 72, as shown in FIG. 3, atemperature regulating pot 86 is fixed to the top of the lower base 54.

In the take-out station 74, as shown in FIG. 3, a shooter 88 for takingout a molded product is mounted on the lower base 54.

On the lower surface of the rotary plate 66, a plurality of, forexample, two neck molds 90 are arranged respectively according to therespective positions of the injection molding station 68, temperatureregulating station 72, blow molding station 70 and take-out station 74.

The neck molds 90 are respectively constituted of split molds and arerespectively mounted on neck support plates 92 constituted of splitplates, while the neck molds 90 can be opened and closed by opening andclosing the neck support plates 92. In the injection stretch blowmolding machine 50, the neck molds 90 and neck support plates 92 forsupporting the same openably and closably constitute a transfer memberto be supported by the rotary plate 66.

The rotary plate 66 can be rotated intermittently by 90° by an electricmotor 94 provided on the upper plate 56 and is capable of transferringsequentially the neck molds 90 to the injection molding station 68,temperature regulating station 72, blow molding station 70 and take-outstation 74.

Here, the rotation stop position of the rotary plate 66 is determined bya positioning mechanism 96. However, it may also be determined only bythe positioning means of a servo motor.

On the upper base 56, there are provided, for example, a temperatureregulating core elevating cylinder 98 situated at the correspondingposition of the temperature regulating station 72 for lifting andlowering a temperature regulating core (not shown), a blow core moldelevating cylinder 102 situated at the corresponding position of theblow molding station 70 for lifting and lowering a blow core mold 100and a stretch rod elevating cylinder 106 for lifting and lowering astretch rod 104, and an eject cam elevating cylinder 110 situated at thecorresponding position of the take-out station 74 for lifting andlowering an eject cam 108 for opening the neck support plates 92.

The cylinder fixing plate 60 is fixed to the upper ends of the two tiebars 62 situated on the injection molding station 68 side above theupper base 56 and, between the cylinder fixing plate 60 and upper base56, there is interposed an injection core mold clamping plate 114 withan injection core mold 112 mounted thereon in such a manner that it canbe lifted and lowered along the two tie bars 62. Here, a cooling mediumcirculates in the injection core mold 112 but description is omitted ofa device for circulating the cooling medium.

Also, on the cylinder fixing plate 60, there is mounted an injectioncore mold clamping cylinder 116, while the leading end of the piston 118of the injection core mold clamping cylinder 116 is connected to theinjection core mold clamping plate 114.

The traction plate 58 is connected and fixed to the lower ends of thefour tie bars 62 within the machine base 52. On the traction plate 58,at a position below the injection molding station 68, there is mounted aneck mold clamping cylinder 120 serving as vertical mold clamping means,while the piston 122 of the neck mold clamping cylinder 120 is connectedto the lower surface of the lower base 54. Here, the vertical moldclamping mechanism of the upper base 56 is configured by the tractionplate 58, tie bars 62 and cylinder 120.

Therefore, as shown in FIG. 3, in a state where the traction plate 58 islifted, when the neck mold clamping cylinder 120 is driven, with thelowering motion of the traction plate 58, the tie bars 62 are towed andlowered and, as shown in FIG. 2, the upper base 56 connected and fixedto the tie bars 62 is lowered by an amount equivalent to a stroke L1.Thus, the neck mold 90 mounted on the rotary plate 66 is lowered and,for example, in the injection molding station 68, the neck mold 90 ismold-clamped relative to the injection cavity mold 78.

Here, on the blow molding station 70 side, the lower surface of theupper base 56 is contacted with a stopper 138 provided on the upperportion of the blow mold clamping mechanism 82 and is positioned at thelower limit position of the upper base 56.

Further, in the temperature regulating station 72 and blow moldingstation 70, the blow mold 84 is clamped to the neck mold 90 by thetemperature regulating pot 86 and blow mold clamping mechanism 82.

Simultaneously when the upper base 56 lowers, the cylinder fixing plate60 fixed to the upper ends of the two tie bars 62 on the injectionmolding station 68 side lowers by the same stroke L1 as the upper base56.

In this state, in the injection molding station 68, by driving theinjection core mold clamping cylinder 116, the injection core moldclamping plate 114 is lowered by a stroke L2 to thereby clamp theinjection core mold 112 and neck mold 90, and the injection apparatus 64injects molten resin into the injection cavity mold 78 to injection molda preform 124.

In this case, since the injection core mold clamping cylinder 116 lowersintegrally with the upper base 56 with the lowering motion thereof, itcan keep the distance constant with respect to the upper base 56.

Therefore, since the lowering stroke L2 of the injection core moldclamping cylinder 116 provides the smallest stroke between theretreating position of the injection core mold 112 from the rotary plate66 and the clamping position, the length of the injection core moldclamping cylinder 116 can be shortened.

Also, since the injection core mold clamping cylinder 116 may onlyprovide a mold clamping force capable of clamping the injection coremold 112, the injection core mold clamping cylinder 116 can be formed tohave a relatively small size.

Here, simultaneously with the molding operation of the injection moldingstation 68, in the temperature regulating station 72, the temperatureregulating core elevating cylinder 98 is operated to insert atemperature regulating core (not shown) into the temperature regulatingpot 86 to regulate the temperature of the preform 124.

Also, in the blow molding station 70, the blow core mold elevatingcylinder 102 is operated to lower the blow core mold 100 to therebyclamp the blow core mold 100 to the neck mold 90; and, the stretch rodelevating cylinder 106 is operated to lower the stretch rod 104 tosupply blow air into the blow mold 84, whereby the temperature regulatedpreform 124 is two-axis stretch blown to mold a bottle 126.

Further, in the take-out station 74, the eject cam 108 is lowered by theeject cam elevating cylinder 110 to open the neck mold 90 through theneck support plate 92, the bottle 126 is dropped down, and the bottle126 is discharged out of the apparatus by the shooter 88. Here, since apair of split plates constituting the neck support plate 92 is normallyclosed by a spring, the neck mold 90 is held in a mold clamped state.Also, the paired split plates include unshown wedge holes respectivelyformed in their two end portions in the longitudinal direction thereof.The opening of the neck mold 90 is attained by lowering the eject cam108 (which is driven by the eject cam elevating cylinder 110) toward thewedge holes to open the split plates.

Next, after the respective molding processes are ended, the blow moldclamping mechanism 82 is operated to open the blow mold 84; the neckmold clamping cylinder 120 is operated to elevate the upper base 56; andthe injection core mold clamping cylinder 116, temperature regulatingcore elevating cylinder 98, blow core mold elevating cylinder 102,stretch rod elevating cylinder 106 and eject cam elevating cylinder 110are operated to retreat the injection core mold 112, temperatureregulating core, blow core mold 100, stretch rod 104 and eject cam 108from their positions in the rotary plate 66, whereby the rotary plate 66becomes rotatable.

In this state, when the electric motor 94 is operated to rotate therotary plate 66 intermittently, the processings in the respectiveprocessing stations can be carried out sequentially.

Also, at a position below the blow molding station 70 of the tractionplate 58, there is provided an auxiliary mold clamping cylinder 128. Theleading end of a piston (not shown) of the auxiliary mold clampingcylinder 128 is connected to the lower base 54 to enable the elevatingand lowering motion of the upper base 56 to balance well on theinjection molding station 68 side and on the blow molding station 70,whereby it can be lifted and lowered smoothly.

Further, the machine base 52 includes synchronizing means 130 forsynchronizing the neck mold clamping cylinder 120 and auxiliary moldclamping cylinder 128.

The synchronizing means 130 includes two racks 132 respectively hangingdown on the injection molding station 68 side and blow molding station70 side of the lower base 54, a rotation shaft 134 stretched between theinjection molding station 68 and blow molding station 70 of the tractionplate 58, and two pinions 136 fixed to the rotation shaft 134 andmeshing with the respective racks 132. Here, in the injection moldingstation 68 as well, there is provided a stopper rod 140 for restrictingsupplementary the lowering limit of the upper base 56.

Here, a blow mold unit 200 to be described below can be applied not onlyto the four-station blow molding machine 50 described above using FIGS.1 to 3 but also to a three-station blow molding machine of a rotarytransfer type, and a blow molding machine for linearly transferring apreform and a container. It can also be applied to an injection blowmolding machine not requiring a stretch processing.

2. Blow Mold Unit

Next, description is given of a blow mold unit 200 with reference toFIGS. 4 to 8. FIGS. 4 to 6 are respectively a front view, a side viewand a plan view of a blow mold unit 200 mounted on the blow moldingmachine 50. In FIGS. 4 and 5, as the structural components of the blowmolding machine 50, there are shown the lower base (base) 54 shown inFIG. 2 and, for example, two elevation rods 150 provided to an elevationdevice such as a hydraulic cylinder. In FIG. 6, there are shown firstand second mold clamping plates 81A, 81B to be driven by a moldclamping/mold opening device 82 shown in FIG. 2.

In the blow mold unit 200 shown in FIGS. 4 to 6, the blow mold 84 shownin FIG. 2 includes first and second blow cavity split molds 210 and 211,and a raised bottom mold 212. The first and second blow cavity splitmolds 210 and 211 respectively have cavities 210A and 211A respectivelycorresponding to the outer shapes of containers. The first blow cavitysplit mold 210, as shown in FIG. 4, has a plurality of, for example,four cavities 210A. The second blow cavity split mold 211 also hasplurality of, for example, four cavities 211A. As shown in FIG. 4, inthe four cavities 210A, 211A provided by the first and second blowcavity split molds 210 and 211, there are provided four raised bottommolds 212 which define the shape of the raised bottom.

In FIG. 4, the first blow cavity split mold 210 includes first pressurereceiving plates 220, 220 on both sides thereof. Similarly, the secondblow cavity split mold 211 includes second pressure receiving plates221, 221 on both sides thereof. The first, second blow cavity splitmolds 210, 211 and first, second pressure receiving plates 220, 221 areclamped by bringing their parting surfaces P into contact with eachother. The first and second pressure receiving plates 220 and 221receive mold clamping pressure.

As shown in FIG. 5, the blow mold unit 200 includes a first fixing plate230 to which the first blow cavity split mold 210 and first pressurereceiving plate 220 are fixed, and a second fixing plate 231 to whichthe second blow cavity split mold 211 and second pressure receivingplate 221 are fixed.

As shown in FIGS. 4 and 5, the blow mold unit 200 includes a thirdfixing plate 232 interposed between the first and second fixing plates230 and 231 and having a first surface 232A to which a plurality ofraised bottom molds 212 are fixed. To a second surface 232B of the thirdfixing plate 232 opposed to the first surface 232A, there are fixed atleast one, for example, two pressure receiving rods 234 hanging downfrom the second surface 232B. The leading ends (engaged portions) 234Aof the two pressure receiving rods 234 can be formed, for example, in atapered pin shape. Also, the pressure receiving rod 234 of thisembodiment includes a flange 234B existing above the engaged portion234A. The flange 234B functions as the lower limit stopper of thepressure receiving rod 234.

Also, the two elevation rods 150 of the elevation device provided to theblow molding machine 50 respectively include, at their leading ends,recessed portions (engaging portions) 151 for receiving the engagedportions 234A of the pressure receiving rods 234. The engaging portions151 and the engaged portions 234A are coupled to each other by theirrespective coupling members 235, and can be lifted and loweredintegrally. Thus, when the elevation rods 150 are lifted and lowered,the plurality of raised bottom molds 212, third fixing plates 232 andpressure receiving rods 234 are lifted and lowered as an integral body.

As shown in FIGS. 4 and 5, there is formed a placement portion 240 whichis removably fixed to at least one of the first and second fixing plates230 and 231 and on which the third fixing plate 232 is placed when thefirst and second blow cavity split molds 210 and 211 are closed. In thisembodiment, the placement portion 240 is constituted of third and fourthpressure receiving plates 240A and 240B capable of receiving moldclamping pressures when the parting surfaces thereof are brought intocontact with each other. The third pressure receiving plate 240A isfixed to the first fixing plate 230, while the fourth pressure receivingplate 240B is fixed to the second fixing plate 231. Thus, the placementportion 240 is also used as the third and fourth pressure receivingplates 240A and 240B. Also, in order to form the container bottomportion shape to be better, in some cases, in the blow moldingoperation, the operation timing of the raised bottom mold is delayed andthe raised bottom mold is elevated over a longer stroke than a normalstroke. In this case, the placement portion 240 may also be formed tohave a lowered height, may be disposed in a position where it does notinterfere with the elevation rods 150, or may be formed at the two sidesurfaces (pressure receiving plates 220, 221 side) of the blow mold.Here, as will be described later, the main function of the placementportion 240 is to prevent the third fixing plate 232 from falling off,and the pressure receiving function is not always essential.

According to this embodiment, when the blow mold unit 200 is carriedinto the blow molding machine 50, the first and second blow cavity splitmolds 210 and 211 are closed. While the first and second blow cavitysplit molds 210 and 211 are closed, the third fixing plate 232 forfixing the plurality of raised bottom molds 212 thereto, as shown inFIG. 5, is placed on the placement portion 240 (third and fourthpressure receiving plates 240A and 240B) fixed to at least one, forexample, both of the first and second fixing plates 230 and 231. Thus,by the first and second fixing plates 230 and 231, not only the firstand second blow cavity split molds 210, 211, first and second pressurereceiving plates 220, 221, but also the plurality of raised bottom molds212 through the placement portion 240 (third and fourth pressurereceiving plates 240A and 240B) and third fixing plate 232 are held.This enables the blow mold unit 200 to be handled as an integral bodyduring the mold replacing.

Here, as shown in FIG. 4, to the lower surfaces of the first and secondpressure receiving plates 220, 221, slide metals 250 shown in FIGS. 7Aand 7B are fixed. The slide metals 250 are used to reduce frictionresistance when opening and closing the blow mold unit on the lower base54 and are made of, for example, oil impregnated metal. As shown inFIGS. 7A and 7B, vertically extending pins 251 are fixed to the slidemetals 250 and screw holes 252 are formed in the slide metals 250.

In the slide metals 250, as shown in FIG. 8, the pins 251 are insertedfrom the lower side into positioning holes formed in the first andsecond pressure receiving plates 220 and 221, and bolts 253 insertedinto bolt holes from the upper side by using holes (hollow portions)220A and 221A formed in the first and second pressure receiving plates220 and 221 are threadedly engaged into the screw holes 252 of the slidemetals 250.

Also, as shown in FIG. 4, rollers 260 are supported on the side surfacesof the first and second pressure receiving plates 220 and 221 in such amanner that they can be moved back and forth from the lower-mostsurfaces of the blow mold unit 200 (the lower surfaces of the slidemetals 250). For this purpose, housings 261 each having an L-shapedsection are fixed to the side surfaces of the first and second pressurereceiving plates 220 and 221. The rollers 260 rotatably supported bymovable blocks 262 are stored within the housings 261. Bolts 263 arethreadedly engaged with the upper portions of the housings 261. Byfastening the bolts 263, the rollers 260 can be pressed down integrallywith the movable blocks 262. The movable blocks 262 and bolts 263 are anexample of a drive member for setting the rollers 260 at the loweredposition.

FIG. 9A shows a state where the roller 260 is pressed down. In thiscase, since the roller 260 rotates in contact with the lower base 54, aclearance δ1 is formed between the lower-most surface (lower surface ofthe slide metal 250) of the blow mold unit 200 and lower base 54.Therefore, by pressing down the roller 260, in the blow mold unit 200,while rolling in contact with the lower base 54, the roller 260 is ableto move on the lower base 54 with reduced friction.

3. Blow Mold Unit Mounting Method

As shown in FIG. 9A, by pressing down the roller 260, the blow mold unit200 is integrally moved on the lower base 54 and is carried into theblow molding portion of the blow molding machine 50. Here, if aremovable positioning pin is provided on the lower base 54 and anengaging portion corresponding to the shape of the positioning pin onthe blow mold unit is provided, since they serve as a guide, thepositioning adjustment of the blow molt unit can be facilitated. Afterthen, by loosening the bolt 263 shown in FIG. 9A, due to the weight ofthe blow mold unit 200, the roller 260 is stored into the housing 261.Accordingly, the blow mold unit 200 lowers by a stroke δ1 from the stateof FIG. 9A and the slide metals 250 are brought into contact with thelower base 54. After then, the mold clamping/mold opening device 82provided to the blow molding machine 50 is driven to bring the first andsecond mold clamping plates 81A and 81B into contact with the first andsecond fixing plates 230 and 231. At this time, the first and secondmold clamping plates 81A and 81B may also be bolt fixed to the first andsecond fixing plates 230 and 231 in advance. Also, if necessary, theelevation rod 150 may be lifted in advance.

Next, when the mold clamping/mold opening device 82 is driven to openthe first and second fixing plates 230 and 231, as shown in FIG. 10, theplacement portion 240 is removed from lower side the third fixing plate232. However, in this case, since the engaged portion 234A of thepressure receiving rod 234 is engaged with the recessed portion(engaging portion) 151 of the elevation rod 150, the third fixing plate232 is prevented from falling off.

In this embodiment, as shown in FIG. 10, when the placement portion 240is removed from the lower side of the third fixing plate 232, the flange234B of the pressure receiving rod 234 is set at a lower limit positionwhere it is brought into contact with the upper end face of theelevation rod 150. In this case, the engaged portion 234A is engagedinto the recessed portion (engaging portion) 151 of the elevation rod150 by a depth δ2. At this time, the third fixing plate 232 and pressurereceiving rod 234 have lowered by δ3 from the upper surface of theplacement portion 240. Here, the setting of the lower limit position isnot limited to the flange 234B but, for example, such setting may alsobe realized only by the engaged portion 234A and engaging portion 151,for example, the lower position may also be defined by the depth of theengaging portion 151 configured by a recessed portion.

By storing the roller 260 from the state shown in FIG. 9A into thehousing 261 to lower the blow mold unit 200, the pressure receiving rod234 with its lowering motion limited to δ3 by the placement portion 240can bring a part of the engaged portion 234A thereof into engagementinto the recessed portion (engaging portion) 151 of the elevation rod150 in advance by a depth of (δ2-δ3). Thus, after then, when the firstand second blow cavity split molds 210 and 211 connected to the moldclamping/mold opening device 82 are opened, the engaged portion 234Afixed to the third fixing plate 232 lowered by δ3 is engaged into theengaging portion 151 from the vertical direction while being guided bythe engaging portion 151, thereby providing a state shown in FIG. 10.

Here, the roller 260 is not always necessary. For example, when thefirst and second fixing plates 230 and 231 are opened as shown in FIG.10, the third fixing plate 232 no longer supported by the placementportion 240 may be dropped by the stroke δ3 to thereby realize theengagement between the engaged portion 234A and the recessed portion(engaging portion) 151. In this case, with respect to the engagementdepth δ2, the relation of δ2=δ3 is established. Or, before the first andsecond fixing plates 230 and 231 are opened as shown in FIG. 10, theelevation rod 150 may be elevated to thereby realize the engagementbetween the engaged portion 234A and engaging portion 151.

As described above, in the case of the engagement between the engagedportion 234A and recessed portion (engaging portion) 151, when theengaged portion 234A has a tapered pin shape, the guide function andcentering function in the engagement are performed, thereby being ableto correct the slight position shift of the third fixing plate 232.However, the guide function and centering function can be realized solong as at least one of the engaged portion 234A and engaging portion151 has a tapered surface. Therefore, instead of, or, in addition to theengaged portion 234A of the tapered pin, the engaging portion 151 mayalso be formed of a tapered hole. Or, the engaged portion 234A may beformed of a tapered hole and, instead of this, or, in addition to this,the engaging portion 151 may be formed of a tapered pin.

Next, as shown in FIG. 4, the pressure receiving rod 234 and elevationrod 150 are coupled to each other by the coupling member 235. This endsthe mounting of the blow mold unit 200. The coupling member 235 isconstituted of two half-divided members which can be opened and closed.The coupling member 235 surrounds and clamps the engaged portion 234A,flange 234B and engaging portion 151. However, the coupling member 235is not limited to this structure. In this embodiment, it is necessary tocouple the coupling member 235 in a state shown in FIG. 4 where thepressure receiving rod 234 has been elevated by δ3 or more from thestate of FIG. 10. Accordingly, even when the first and second blowcavity split molds 210 and 211 are closed, interference between thethird fixing plate 232 and placement portion 240 can be prevented. Thus,it is necessary to lift the raised bottom mold 212, third fixing plate232 and pressure receiving rod 234. However, since their total weight issmall when compared with the total weight of the first and second blowcavity split molds 210 and 211, first and second pressure receivingplates 220 and 221 and first and second fixing plates 230 and 231, theworkload can be greatly reduced when compared with prior art. Here,since the placement portion 240 is necessary when mounting the blow moldunit 200, after the mounting of the coupling member 235 is ended, theplacement portion 240 may be removed. However, as in this embodiment,when the placement portion 240 is used also as the third and fourthpressure receiving plates 240A and 240B, it is not necessary to removethe placement portion 240.

4. Blow Mold Unit Height Adjusting Method

After the blow mold unit 200 is mounted as mentioned above, the heightof the blow mold unit 200 can be adjusted. Firstly, the neck molds 90(see FIG. 3) and first and second blow cavity split molds 210 and 211are temporarily clamped to determine whether the height of the first andsecond cavity split molds 210 and 211 is proper or not. When not proper,as shown in FIGS. 9B and 11, a clearance δ4 is secured between thelower-most surfaces of the first and second pressure receiving plates220, 221 and slide metals 250, shim plates 270 shown in FIG. 12 areinserted, and the height of the blow mold unit 200 is adjusted. In thiscase, the bolts 253 for fixing the slide metals 250 shown in FIG. 8 canbe operated from above and loosened using the holes (hollow portions)220A and 221A formed in the first and second pressure receiving plates220 and 221. After then, as shown in FIG. 9B, by lowering the rollers260, there can be secured the clearances δ4 between the lower-mostsurfaces of the first and second pressure receiving plates 220 and 221and slide metals 250. In this manner, the rollers 260 can be used notonly when they are rolled on the lower base 54 in contact therewith tocarry in the blow mold unit 200 but also when the height of the blowmold unit 200 is adjusted.

After then, as shown in FIG. 12, the shim plates 270 can be insertedbetween the lower-most surfaces of the first and second pressurereceiving plates 220 and 221 and slide metals 250. The shim plate 270has a U-like shape which can be positioned by a positioning pin 251 anda bolt 253. After insertion of the shim plates 270, when the rollers 260are lowered and the bolts 253 are fastened to fasten the slide metals250 to the lower-most surfaces of the first and second pressurereceiving plates 220 and 221, the height adjustment is ended.

Although description has been given specifically of the embodiment, itis easy for a person skilled in the art to understand that variousmodifications are possible without departing substantially from the newmatters and effects of the invention. Therefore, such modifications areto fall under the scope of the invention. For example, any terms used atleast once together with different terms of broader or synonymous sensein the specification or drawings can be replaced with such differentterms in any portions of the specification and drawings.

For example, the invention is not limited to a blow molding machine of arotation transfer type but can also be similarly applied to a blowmolding machine of a horizontal transfer type.

The present application is based on Japanese Patent Application No.2011-232359 filed on Oct. 24, 2011 and the contents thereof areincorporated herein for reference.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

50: blow molding machine

54: base (lower base)

81A, 81B: first and second mold clamping plates

82: mold clamping/mold opening device (blow mold clamping mechanism)

84: blow mold

150: elevation rod

151: engaging portion

200: blow mold unit

210, 211: first and second blow cavity split molds

212: raised bottom mold

220: first pressure receiving plate

220A: hollow portion

221: second pressure receiving plate

221A: hollow portion

230: first fixing plate

231: second fixing plate

232: third fixing plate

232A: first surface

232B: second surface

234: pressure receiving rod

234A: engaged portion

234B: flange

235: coupling member

240: placement portion

240A: third pressure receiving plate

240B: fourth pressure receiving plate

250: slide metal

251: pin

252: screw hole

253: bolt

260: roller

262, 263: roller drive member

270: shim plate

1. A blow mold unit to be connected to first and second mold clampingplates movable such that they are symmetrical to each other by a moldclamping/mold opening device of a blow molding machine and an elevationdevice of the blow molding machine, the blow mold unit comprising: ablow mold including first and second blow cavity split molds to beclamped by bringing mold parting surfaces thereof into contact with eachother, and a plurality of raised bottom molds that define a plurality ofraised bottom shapes for a plurality of cavities defined by the firstand second blow cavity split molds; first and second pressure receivingmembers that have parting surfaces and that receive mold clampingpressure by bringing the parting surfaces into contact with each other;a first fixing plate to which the first blow cavity split mold and thefirst pressure receiving member are fixed and to be connected to thefirst mold clamping plate; a second fixing plate to which the secondblow cavity split mold and the second pressure receiving member arefixed and to be connected to the second mold clamping plate; a thirdfixing plate interposed between the first and second fixing plates andto which the plurality of raised molds are fixed at a first surfacethereof; a pressure receiving rod extending down from a second surfaceof the third fixing plate opposed to the first surface; and a placementportion fixed to at least one of the first and second fixing plates andplacing the third fixing plate thereon when the first and second blowcavity split molds are closed, wherein a low part of the first pressurereceiving member includes a first hollow portion, and a low part of thesecond pressure receiving member includes a second hollow portion, andwherein a first engaging portion of the pressure receiving rod isengageable in a vertical direction with a second engaging portion of anelevation rod of the elevation device.
 2. The blow mold unit accordingto claim 1, wherein a tapered surface is formed on at least one of thefirst engaging portion of the pressure receiving rod and the secondengaging portion of the elevation rod, and the second engaging portioncenters and guides the first engaging portion.
 3. The blow mold unitaccording to claim 1, wherein the placement portion includes third andfourth pressure receiving members that receive the mold clampingpressure by bringing the parting surfaces thereof into contact with eachother, the third pressure receiving member being fixed to the firstfixing plate, and the fourth pressure receiving member being fixed tothe second fixing plate.
 4. The blow mold unit according to claim 1,wherein the first and second pressure receiving plates each include: aroller rollingly contacting with a base of the blow molding machine; anda roller drive member that drives the roller lower from an elevatedposition where the roller does not project from a lower-most surface ofthe blow mold unit to a lowered position where the roller rollinglycontacts with the base.
 5. The blow mold unit according to claim 4,wherein the first pressure receiving member is fixed to the first fixingplate at both sides of the first blow cavity split mold, wherein thesecond pressure receiving member is fixed to the second fixing plate atboth sides of the second blow cavity split mold, wherein a first slidemetal is fixed to a lower-most surface of the first pressure receivingmember and a second slide metal is fixed to a lower-most surface of thesecond pressure receiving member, wherein the first slide metal includesa first pin insertable into a first hole formed in the lower-mostsurface of the first pressure receiving member and a first screw hole towhich a first bolt is threadedly engaged in the first pressure receivingmember, and the second slide metal includes a second pin insertable intoa second hole formed in the lower-most surface of the second pressurereceiving member and a second screw hole to which a second bolt isthreadedly engaged in the second pressure receiving member, and whereina first bolt hole is formed to penetrate from an upper surface facingthe first hollow portion to the lower-most surface of the first pressurereceiving member and the first bolt is inserted into the first bolt holefrom the upper side and is threadedly engaged to the first screw hole,and a second bolt hole is formed to penetrate from an upper surfacefacing the second hollow portion to the lower-most surface of the secondpressure receiving member and the second bolt is inserted into thesecond bolt hole from the upper side and is threadedly engaged to thesecond screw hole.
 6. A blow molding machine comprising: a base; a blowmold unit which is supported on the base, the blow mold unit including:a blow mold including first and second blow cavity split molds to beclamped by bringing mold parting surfaces thereof into contact with eachother, and a plurality of raised bottom molds that define a plurality ofraised bottom shapes for a plurality of cavities defined by the firstand second blow cavity split molds; first and second pressure receivingmembers that have parting surfaces and that receive mold clampingpressure by bringing the parting surfaces into contact with each other;a first fixing plate to which the first blow cavity split mold and thefirst pressure receiving member are fixed and to be connected to thefirst mold clamping plate; a second fixing plate to which the secondblow cavity split mold and the second pressure receiving member arefixed and to be connected to the second mold clamping plate; a thirdfixing plate interposed between the first and second fixing plates andto which the plurality of raised molds are fixed at a first surfacethereof; a pressure receiving rod extending down from a second surfaceof the third fixing plate opposed to the first surface; and a placementportion fixed to at least one of the first and second fixing plates andplacing the third fixing plate thereon when the first and second blowcavity split molds are closed, wherein a low part of the first pressurereceiving member includes a first hollow portion, and a low part of thesecond pressure receiving member includes a second hollow portion, andwherein a first engaging portion of the pressure receiving rod isengageable in a vertical direction with a second engaging portion of anelevation rod of the elevation device; a mold clamping/mold openingdevice provided on the base and drives the first and second fixingplates of the blow mold unit to clamp/open the first and second blowcavity split molds; and an elevation device that drives an elevation rodto lift and lower the plurality of raised bottom molds of the blow moldunit.